It appears that necessity is a dead idea that, unfortunately, only philosophers still gush over. The association of epistemological and logical necessity with ontological necessity ran its course from Aristotle up to the mid-nineteenth century. This long tradition assumed that the basis of metaphysical knowledge stems from the structure of necessity and outdated essentialist actuality. Tied to this notion is the claim of rationality referred to by mainstream analytic philosophers today. But this has become untenable and scientists have based rationality on the methods of possibility and probability instead. Even the way laws of nature are generalized they are not meant to be irreformable or taken in any universal sense.

As philosophers Randall Auxier and Gary Herstein have written,

Knowledge today does not require necessity of any kind –logical, psychological/cognitive/epistemological, or ontological. Even the movements, following C.I. Lewis, to reinvent logic so as to deal effectively with possibility, have been rendered largely pointless because they have clung to various modes of necessity to account for possibility, with each version of modal logic interpreting possibility according to a slightly varied sense of necessity and its corresponding notion of validity. So long as necessity is taken to be the guarantor of rationality, the conception of rationality advocated will be as useless to science as it is to practical life.

If one neither affirms nor denies the reality of ontological necessity, then what justifies positing it as an ungrounded principle in our philosophies? Given the pragmatic and hypothetical tone of the sciences, may its reliance on necessity help explain the difficulty philosophy has in being heard and taken seriously as a cultural form?

  • According to Whitehead it has hindered the imagination and given us false senses of certainty or superiority. You seem to be assuming the current conditions are the norm, but they are not. History needs to be taken seriously and folks need to be aware of this transition and why it is important. You should not take what you say for granted because for sooooo long it wasn't so! I think your response confirms the need to address the views that don't see it as simply as you have laid out. This is a question of immense importance whether metaphysically, scientifically, ethically, ect. Jul 23, 2013 at 21:05
  • Why did the tradition end in mid-19th century? Jul 24, 2013 at 14:59
  • At least in philosophy, people caught onto Kant's notion of putting the possible before the actual. It was advanced through the German Idealists and picked up by the existentialists. We were enfranchised from necessity by Kant because it was always thought to be "necessary" that nothing is possible unless it first is brought into actuality. Kant abandoned this crucial assumption and started questioning why the possible must be subordinate to the actual. Jul 24, 2013 at 16:41
  • I like this part ""Given the pragmatic and hypothetical tone of the sciences, may its reliance on necessity help explain the difficulty philosophy has in being heard and taken seriously as a cultural form? " I think philosophy needs to have practical ramifications and practical applicability. philosophy needs to have relevance to the day to day lives of people. its good that it establishes and promotes an inquisitive mind but it needs to go beyond that. it then just becomes a talk shop without practical ramifications. Jan 13, 2014 at 17:57
  • Well stated--I couldn't agree more. Yes, there is a bigger problem with philosophy's relevancy. I always offer my classes extra credit to name a famous philosopher--who is alive and not a teacher they took! It is amazing how quiet it gets. Many have done away with philosophy because they have to "get ur done," and the economic motives, hustle-and-bustle doesn't encourage it. But I don't think this is very wise and ends up being their loss. Philosophy is about reflection and the study of our abstractions. Individuals and cultures are enhanced by philosophical value/contribution just as well. Jan 19, 2014 at 2:31

4 Answers 4


Given that there is

(1) a need for expressing that "x is impossible" (with "impossible" being interpreted in some sense) and

(2) we accept that "possible(x) <-> not necessary(not x)" (with "necessary" being understood so that it matches the interpretation of "possible").

then I cannot see how the concept of necessity can be avoided.

  • Could you elaborate on that? Why is expressing impossibility necessary and how is that not circular reasoning?
    – iphigenie
    Jul 23, 2013 at 8:14
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    @iphigenie: My point was not about whether "expressing impossibility [is] necessary", but that possibility and impossibility are conceptually connected to necessity; so if one wants to use the former, the latter seems inevitable. If p is necessarily true, then it is not possible that p is false. In formal terms: necessary(p) -> not possible(not p). This implies possible(not p) -> not necessary (p) i.e. if it is possible that p is false, then p is not necessarily true. Adding the proper negations, the concepts of necessity and possibility are interchangeable.
    – chela
    Jul 25, 2013 at 6:57

I like your introductory paragraph. You should expand on that elaboration, maybe in simpler terms. Beware that I'm from a scientific background. Now your two questions.

If one neither affirms nor denies the reality of ontological necessity, then what justifies positing it as an ungrounded principle in our philosophies?

Who is we and what are our philosophies? If you say that necessity has such an important foundational status, then you're implying we make our arguments depend on it. I don't quite see this. I feel philosophy now is more asking questions than giving answers. I think the only philosophical deductions which are for the ages are of the form "If we agree on these formal chains of reason in analytical logic, then this letters on my page lead to these". It only gets dangerous if one claims that the formal expression "P => Q" can actually be interpreted as saying something about reality - and I think many philosophers themselves think in the modern scientific way you describe: "A formal logical deduction might be used to say something about the real world, but when it happens not to be applicable, then it just isn't and we shouldn't a priori expect it". What I say here is that, just like scientists, many philosophers don't even believe in "reality of ontological necessity", because they are themselves brought up in a more or less scientifically literate world.

Given the pragmatic and hypothetical tone of the sciences, may its reliance on necessity help explain the difficulty philosophy has in being heard and taken seriously as a cultural form?

By cultural form do you mean everyday culture or the academic realm? Either way, my answer is no, I don't think that this is the reason, simply because I don't think enough people think about it to that extent. Time after time, fields of study have been exported from philosophy to stand-alone sciences. When non-philosophers think of "philosophy", they now equate it with "history of western philosophy". And they might be right to some extent; I feel that philosophers often try to philosophize on topic within a field - but to do so, just to grasp what philosophical solutions are needed in that area, they would have to study the field, becoming scientists themselves. If this route is to be avoided, then philosophers "should" focus on the meta questions of the field of study, e.g. why study it at all, what should be the goal etc.

It would be tremendously interesting to me what actually motivates people to argue for this and that. Example: Yesterday I was browsing here on Philosophy.SE and I learned there is a "movement" called Speculative realism. The topic itself has nothing to do with the point but I want to say that there are >9000 point of views, and more you could potentially come up with in the future, which one could defend. Now in the sciences, e.g. if you investigate the brain, or if you work in the field of superconductors, then this is your job and so you do what you do. There is an empirical goal, may it be justified or not. On the other side, I have no insight into what extent people who talk about this and that worldview are actually motivated by some personal desire to... I don't know. Why do they even want to convince someone else? "Rationally speaking", the chance that their point of view is the "right" one (if there is such a thing) is minor. After all, there are other clever people with opposing points of view. So coming to your questions, most people compare the scientific fields and are not into it enough to get the why part. Science has made us expect results which we can see, in a plastic way.

I guess I kind of feel the same. If the reason is that philosophers want to change something they don't like in the world, then I'm pretty sure there are more direct ways to achieve it. So I think "having fun" doing it might be the motivator. Or do they talk about it because it's their job, and a nice one at that? The sad truth is, that I think a major factor is that academics want to get academic recognition. Just like the people in the sciences. It's natural, I don't blame anyone really, but it leads me to believe that what they do is not really important. It gives an interesting cultural background at least.

Coming back: Often times people (including philosophers) argue for a point which they would like to be changed (e.g. a moral or cultural issue) and while trying to find arguments which support their position (which might bring some advantage to their personal situation) they speak as if they it was clear that one could still rely on validity of concepts like necessity in the real world.

I want to emphasise "in the real world" in the last sentence. I don't think that one should confuse the string "box = not karo not" etc. with the concepts of real world necessity, even if that has many applications and captures our intuition.

  • Good response! I'm very appreciative for the feedback and will attempt to digest it. Thank you, Nick! Jul 23, 2013 at 21:01
  • @MMJ: Good. I later saw your self-description on your user page and wasn't sure anymore if you asked for an answer from such a scientific perspective. In the end, I'm also not particularly happy with my own answer, because the last sections can be read as a purpose-of-philosophy question, when I'm in fact usually trying to come from the other side. Well at least it reflects what I think people think about the subject, maybe unconsciously. / The question what you mean by cultural form still stands for me and the request for you writing down your first paragraph in more detail was serious too.
    – Nikolaj-K
    Jul 23, 2013 at 21:06
  • What up, Nick! Sorry for the delay. I am borrowing the term from Ernst Cassirer's philosophy of symbolic forms, which is nicely summarized in his excellent book An Essay on Man. Whitehead along with Eric Voegelin, also share this theory of cultural interests that recognizes the value of these domains without reducing culture to any combination of them. It is largely an organic and cell-theory of community which takes human freedom as the creation or destruction of the various cultural symbolic forms or interests. It is an open and pluralistic approach to cultural values and interpretations. Jan 19, 2014 at 18:34

What's the difference between arbitrarily high probability and certainty?

This question briefly piqued my interest but upon pondering the idea, it quickly occurred to me to be a futile question, as I don't see how you could go anywhere with it. I don't see the advantage nor use of a logic that has no way of expressing necessity. Consider the following argument:

Socrates is a man.  
All men are mortal.  
Therefore, Socrates is (necessarily) mortal.

If you were to explain that without necessity, you would get an expression of probability that would be arbitrarily close to necessity, such as "almost certainly" (in Math) such that they would be functionally the same.

Has necessity really harmed science?

More importantly, as a scientist myself, I also don't see how the use of necessity has harmed science at all; on the contrary, I think it has been a profoundly useful guide in separating fact from fiction so as to arrive as close as we can to the truth. Also, "necessity" is not at odds with "possibility"; I don't see a conflict there at all, and find that science is all about both.

The link between philosophy's popular acceptance and necessity

Given the pragmatic and hypothetical tone of the sciences, may its reliance on necessity help explain the difficulty philosophy has in being heard and taken seriously as a cultural form?

I think you'd be hard-pressed to prove that science's reliance on "necessity" has anything to do with philosophy "being taken seriously as a cultural form". To be a philosopher was once a very respectable position to have. The difficulty is that it has almost always been the province of the wealthy — if you were of the working class you more likely had to spend most of your day putting food on the table. To have access to the rich philosophy that came before us, you had to have had the luxury of an education, and even then, the logical mind for it. Philosophy's current position, I would argue, is simply because A) in our modern society being a philosopher won't get you paid and we tend to greatly value money, and B) the ideas/concepts remain rather obtuse to the layperson. Most people, I'm afraid, do not have the training, discipline of mind, or even willingness to learn philosophy because it will appear to have no practical use to them. I can't see how removing "necessity" from philosophy would change that.

  • -1: We have heard all this before and you are parroting a long tradition. There are many who have philosophical "training," yet they substitute "uncertain truths" with "certain untruths." Philosophy is about asking questions--piety of thinking--not giving answers! Necessity has held some of the best minds back from this, including Plato and Aristotle. I appreciate the admission you are not as familiar with the history of metaphysics. But using a monotonic example from outdated logic illustrates the point! It's not black and white; what do you do when fact becomes fiction and vice versa? Jul 24, 2013 at 13:00
  • Please let me know when you or anybody finds "truth," but I don't know how helpful it would be or what else we would need to live for. Holding on to necessity is more like a pathology then anything constructive. There is no need to run down "the layperson" or "most people" as your answer ends with unneeded stereotyping. If they don't have this training it may be a good thing; they probably aren't as constrained. Philosophy struggles to get at the fringe to deal with the immediacies of life and doesn't need to conform to necessity or some static category to have it make sense. Jul 27, 2013 at 13:36
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    Your syllogism example is played out, you assume the same Socrates in premise one and the conclusion. It disregards temporal relations and that's one of the big problems with necessity. Now that's a mind game! Not to mention it's boring and uninteresting! I happen to believe that philosophy can serve further ends, even starting with the admission that it can be a type of madness. Jul 27, 2013 at 13:42
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    You jump to a lot of conclusions, sir. :\
    – stoicfury
    Jul 27, 2013 at 18:39
  • I respect what you're saying and will give it some thought. Jul 28, 2013 at 14:10

Even if the sciences have abandoned neccessity and embraced possibility & probability one should be careful, I think about the ontological & epistemological ramifications, and also the ongoing usage of neccessity within the sciences. One, I think is dealing with a more expansive world.

A case in point: The discovery of non-euclidean geometry makes it appear that one has to abandon euclidean geometry. This is far from the case. Locally the geometry of a non-euclidean space is still euclidean. And in fact this is what is used to define in contemporary usage the idea of non-euclidean space. (The idea of locality in this sense is a major theme in contemporary mathematics).

Perhaps, then one should then say that although globally the cosmos in its most general term being contingent, one can still say locally neccessity holds (in manifold forms). I do not, for example, expect to wake up tommorow and see the sun fall out of the sky. When cosmologists extrapolate to micro-seconds before the big-bang the more careful amongst them know that they are doing highly speculative physics, but of neccessity they can only use what is known at present, as well as speculative moves that make sense within the larger picture and understanding of physics.

Borrowing terminology from geometry, perhaps then one can talk about possibility being a kind of curvature of neccessity (given that a broad form of logic is geometrical).

I'll take it for granted, as you say, that the necessity has been a major theme in Western Philosophy say since from Aristotles time, as I'm not at all well versed in intellectual history, and perhaps reinforced by a Christian theology of God as a neccessary ground of being. Although I tend to suspect that this is the influence of Greek thought on Christianity. However it wouldn't surprise me that there could be a possible minoritarian position that poses the opposite, that has led a kind of underground existence, following Hericlites lead.

One can, I suppose fruitfully contrast this with the Taoist thought, where contingency is emphasised on a cosmic level, and on an epistemological level - for example, the first two lines of the Tao:





The Dao that can be trodden is not the enduring and unchanging Dao

The name that can be named is not the enduring and unchanging name

James Legge translation

And of course this contingency is reflected in certain forms of traditional calligraphy, where aspects of organic transience is emphasised (a form that only found expression in Western art in the action paintings of Pollack - but his scale was very different).

But would you not say, that after Nietszche broke the link with the infinite ground of God, that neccessity must also give way?

  • Interesting! Well stated! Jul 24, 2013 at 12:51

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